Downhole jetting tool

Abstract

There is provided a jetting tool assembly for use in cleaning tubular components used in drilling for gaseous or liquid hydrocarbons in producing formations, said assembly being connectable to a hollow drillstring and having a first mode of operation which allows through-flow of fluid and lengthwise of the drillstring, and a second mode of operation which routes the fluid transversely outwardly of the drillstring.

What is claimed is:  
     
       1. A jetting tool assembly for use in cleaning tubular components used in drilling for gaseous or liquid hydrocarbons in producing formations, said assembly being connectable to a hollow drill string and having a first mode of operation which allows through-flow of fluid and lengthwise of the drill string, and a second mode of operation which routes the fluid transversely outwardly of the string, in which the assembly comprises: 
       a hollow main body through which axial flow of fluid can take place between an inlet end and an outlet end of the main body, in the first mode of operation;  
       an outlet port in the wall of the main body through which fluid can flow transversely of the drillstring in the second mode of operation;  
       a control sleeve slidably mounted in the main body for movement between a first position in which it blocks communication between the interior of the main body and said outlet port and a second position in which it allows communication between the interior of the main body and said outlet port means;  
       a biasing arrangement urging the sleeve in a direction towards said first position;  
       a ball-receiver arrangement at one end of the sleeve to receive a ball when the latter is launched down the drillstring to activate the tool assembly, said arrangement being operative when engaged by a launched ball to move the sleeve to the second position against the biasing arrangement, and returning the sleeve to the first position under the action of the biasing arrangement upon dislodgement of the ball;  
       a jetting body mounted externally on the main body; and  
       one or more jet outlet in the wall of the jetting body and communicating with said outlet port so as to direct fluid outwardly against the internal wall of a surrounding tubular component for cleaning purposes when the tool assembly has been activated.  
     
     
       2. A tool assembly according to  claim 1 , in which the outlet port communicates with said jet outlets via an annulus provided in the outer surface of the main body. 
     
     
       3. A tool assembly according to  claim 1 , in which the jetting body is slidable lengthwise of the main body during assembly, and is retained against longitudinal displacement when assembled. 
     
     
       4. A tool assembly according to  claim 3 , including spline and groove interfit between the main body and the jetting body, to permit slidable movement for assembly and disassembly purposes. 
     
     
       5. A tool assembly according to  claim 4 , in which the splines and grooves are circumferentially spaced at equal distances, to allow relative angular adjustment to compensate for any erosive wear on the internal surface of the main jetting body. 
     
     
       6. A tool assembly according to  claim 1 , including one or more plug inserts locatable in a respective jet outlet to facilitate dislodgement of debris. 
     
     
       7. A tool assembly according to  claim 1 , including a displaceable retainer flap arranged in the path of travel of an activating ball, when the latter is displaced from engagement with the ball receiver arrangement in order to deactivate the tool assembly, said retainer flap arrangement returning to a closed position preventing return of a ball after being received by the ball catcher device.